JP7834845B2 - A method for manufacturing wafers using peel tape and adhesive, and peel tape and adhesive used in the method. - Google Patents

Description

The present invention relates to a method for manufacturing a wafer, and more specifically, to a method for manufacturing a wafer, which includes a step of peeling off the adhesive material that temporarily fixed the wafer to the support using peel tape after processing the wafer, in which the wafer is processed or otherwise treated while the wafer is temporarily fixed to a support.

In semiconductor manufacturing processes, temporary fixing is often necessary or preferable during wafer processing due to the thinness and fragility of the wafers. For example, thin grinding of wafers on which functional layers for semiconductor devices are formed is widely performed to achieve high integration of semiconductor devices. However, when grinding to the extreme thinness, the wafer cannot be supported by tape alone, and it has been proposed to temporarily fix the wafer to a hard carrier (support) via an adhesive material before processing after thin grinding. Semiconductor manufacturing processes using such supports are called wafer support systems.
In the wafer manufacturing process using a wafer support system, after processes such as thin grinding of the wafer, it is necessary to detach the support from the wafer and then remove the adhesive material that temporarily fixed the wafer and support together.
As a method for removing adhesive materials, a method is known in which a release tape is applied and then peeled off, thereby removing unwanted materials from the semiconductor wafer together with the release tape (Patent Document 1). In addition, a method for removing temporary fixing material using an adhesive sheet (adhesive tape) that can be easily removed from the wafer, and such adhesive sheets have been proposed (Patent Documents 2 and 3).
Furthermore, an adhesive that can be removed from wafers more easily has been proposed (Patent Document 4).
However, even when these release tapes, adhesive tapes, or adhesives were used, it was not easy to peel the adhesive from the edges, and some of the adhesive remained on the wafer during peeling, resulting in so-called adhesive residue, which sometimes affected the wafer yield.

Japanese Patent Publication No. 2002-124494 Japanese Patent Publication No. 2009-275060 Special table 2015-518270 publication International Publication No. 2017/221772 A1

In view of the above technical background, an object of the present invention is to provide a wafer manufacturing method that includes a step of peeling the adhesive from a laminate A consisting of a wafer and an adhesive using a peel tape, and which enables the peeling of the adhesive from the laminate A consisting of a wafer and an adhesive more easily and stably than conventional peeling methods. Furthermore, a further object of the present invention is to provide an adhesive and a peel tape that can be peeled more easily and stably than conventional methods.

The adhesive material is used in a wafer processing method (wafer support system) in which the wafer is temporarily fixed to a support and then processed, such as by grinding. The adhesive material has surfaces A and B, and surface A is attached to the support and surface B is attached to the wafer to temporarily fix the support and the wafer, and is used for wafer processing.
After processing a wafer, the support is removed to obtain a laminate A consisting of the wafer and an adhesive. The present invention relates to a method for removing the adhesive from this laminate A.
The adhesive material may have an adhesive layer having surface A and an adhesive layer having surface B, and preferably it may have a peel tape side adhesive layer, a base film, and a wafer side adhesive layer. Alternatively, the adhesive material may be a single layer of adhesive obtained by curing a semi-liquid or liquid adhesive. In this case, it has a peel tape side adhesive layer and a wafer side adhesive layer made of the same material.

As a result of diligent research, the inventors of the present invention have discovered that by using a peel tape and adhesive in which the ratio of the peel strength of the peel tape/adhesive to the peel strength between the adhesive and a specific wafer, measured under specific conditions, satisfies specific conditions, the adhesive can be stably peeled off relatively easily from a laminate A consisting of a wafer and adhesive, thus completing the present invention.

In other words, the present invention and its various embodiments are as follows. However, the present invention is not limited to the following.
[1]
A method for manufacturing wafers,
The process includes a step of peeling the adhesive from a laminate A consisting of a wafer and an adhesive using a peel tape, and in the step,
A method for manufacturing a wafer, using the peel tape containing a silicone-based adhesive component in the adhesive layer that contacts the adhesive material, and the adhesive material having _P1 and _P2 that satisfy the following conditions: the peel strength ratio _P1 / _P2 is 6 or more, and _P2 is 0.5 N/25 mm or more:
However, the adhesive material has a surface A that contacts the peel tape and a surface B that contacts the wafer, _P1 is the peel strength on surface A when the peel tape is held at 90° relative to the adhesive material and measured, and _P2 is the peel strength on surface B when the adhesive material is held at 90° relative to the polyimide coated wafer and measured.
[2]
The method for manufacturing a wafer according to [1], wherein the layer having surface A of the adhesive material contains a silicone-based adhesive component or a silicone release agent.
[3]
The method for manufacturing a wafer according to [1] or [2], wherein the adhesive material comprises at least a wafer-side adhesive layer, a base film, and a peel tape-side adhesive layer.
[4]
A method for peeling off an adhesive from a laminate A consisting of a wafer and an adhesive using a peel tape,
The peeling method uses the peel tape containing a silicone-based adhesive component in the adhesive layer that contacts the adhesive material, and the adhesive material having _P1 and _P2 that satisfy the following conditions: the peel strength ratio _P1 / _P2 is 6 or more, and _P2 is 0.5 N/25 mm or more:
However, the adhesive material has a surface A that contacts the peel tape and a surface B that contacts the wafer, _P1 is the peel strength on surface A when the peel tape is held at 90° relative to the adhesive material and measured, and _P2 is the peel strength on surface B when the adhesive material is held at 90° relative to the polyimide coated wafer and measured.
[5]
The peeling method according to [4], wherein the layer having surface A of the adhesive material contains a silicone-based adhesive component or a silicone release agent.
[6]
The peeling method according to [4] or [5], wherein the adhesive material comprises at least a wafer-side adhesive layer, a base film, and a peel tape-side adhesive layer.
[7]
A viscous adhesive used in the wafer manufacturing method or peeling method described in [1] to [6], wherein _P2 is 0.5 N/25 mm or more.
[8]
A peel tape used in the wafer manufacturing method or peeling method described in [1] to [6], wherein the peel tape comprises at least a base film and an adhesive layer, and the adhesive layer contains a silicone-based adhesive.
[9]
The peel tape according to [8] , wherein the base film of the peel tape comprises at least one of polyimide, polyester, or fluororesin.

According to the wafer manufacturing method of the present invention, the adhesive can be easily and stably removed from the wafer after processing such as thin grinding, so that no adhesive residue or damage to the wafer occurs, and the process can be carried out with high productivity and yield, which greatly contributes to improving the productivity of electronic components such as electronic devices.

This is a schematic diagram illustrating a method for measuring peel strength _P1 using a sample for measuring peel strength _P1 . However, components that do not contribute to peel strength _P1 , such as the wafer-side adhesive layer of the adhesive material, are omitted, and the ratios of the dimensions of each component in the diagram do not necessarily reflect the actual ratios. This is a schematic diagram illustrating a method for measuring peel strength _P2 using a sample for measuring peel strength _P2 . However, components that do not contribute to peel strength _P2 , such as the adhesive layer on the peel tape side of the adhesive material, are omitted, and the ratios of the dimensions of each component in the diagram do not reflect the actual ratios in some parts. This is a schematic diagram showing a laminate consisting of peel tape, adhesive, and wafer when using double-sided tape with a base film as the adhesive. However, some of the ratios of the dimensions of the components in the diagram do not reflect the actual ratios. This is a schematic diagram illustrating a method for evaluating the removeability from a wafer, specifically a method for creating a laminate A consisting of a wafer and adhesive by removing the support from a laminate B consisting of a support, adhesive, and wafer. However, for the sake of simplification, the adhesive is shown as a single-layer structure, and the ratios of the dimensions of the components in the diagram do not necessarily reflect the actual ratios. This is a schematic diagram illustrating a method for evaluating the removeability from a wafer. However, for the sake of simplification, the adhesive is shown as a single-layer structure, and the ratios of the dimensions of each component in the diagram do not necessarily reflect the actual ratios.

The present invention
A method for manufacturing wafers,
The process includes a step of peeling the adhesive from a laminate A consisting of a wafer and an adhesive using a peel tape, and in the step,
A method for manufacturing a wafer using the peel tape containing a silicone adhesive in the adhesive layer that contacts the adhesive material, and the adhesive material having _P1 and _P2 that satisfy the following conditions: the peel strength ratio _P1 / _P2 is 6 or more, and _P2 is 0.5 N/25 mm or more:
However, the adhesive material has a surface A that contacts the peel tape and a surface B that contacts the wafer, _P1 is the peel strength on surface A when the peel tape is held at 90° relative to the adhesive material and measured, and _P2 is the peel strength on surface B when the adhesive material is held at 90° relative to the polyimide coated wafer and measured.
That is the case.
In other words, the wafer manufacturing method of the present invention uses an adhesive and a peel tape.

The adhesive material used in the wafer manufacturing method of the present invention has _P1 and _P2 that satisfy the following conditions: the peel strength ratio _P1 /P2 is 6 or more, and _P2 is 0.5 N/25 mm or _more . However, the adhesive material has a surface A that contacts the peel tape and a surface B that contacts the wafer, _P1 is the peel strength on surface A when the peel tape is kept at 90° relative to the adhesive material and measured, and _P2 is the peel strength on surface B when the adhesive material is kept at 90° relative to the polyimide coated wafer and measured.

Peel strength _P1 indicates the adhesive strength on surface A (i.e., between the peel tape and the adhesive), and peel strength _P2 indicates the adhesive strength on surface B (i.e., between the adhesive and the wafer). In evaluating peel strength _P2 , a polyimide-coated wafer is used as the wafer for peel strength measurement to measure the peel strength between the adhesive and the polyimide-coated wafer.

The peel strengths _P1 and _P2 of the adhesive used in the present invention are the force (N/mm) per unit width of the peeled portion required to allow peeling to proceed while maintaining an angle of 90° between the peeled layers (peel tape and adhesive, or adhesive and wafer).
In other words, peel strengths _P1 and _P2 are determined by measuring the force required for peeling by allowing the peel tape/adhesive or adhesive/wafer to delaminate in the state shown in Figure 1 or a similar state. The measured value can be determined by dividing it by the width of the peeled portion, and more specifically, it can be measured by the following method.

When measuring the peel strength _P1 between peel tape and adhesive, the measurement can be performed using a sample for measuring peel strength _P1 without a wafer (Figure 1(a)).
A sample for measuring peel strength _P1 can be obtained, for example, by fixing the wafer-side adhesive layer of the adhesive material to an acrylic plate (not shown) via double-sided tape. Before fixing the adhesive material to the acrylic plate, a treatment such as heating may be performed, simulating the actual wafer manufacturing process. After attaching the adhesive layer of the peel tape to the 22 peel tape-side adhesive layer of the adhesive material of the obtained sample for measuring peel strength _P1 using a predetermined method, the peel strength _P1 can be measured by peeling off the peel tape while maintaining an angle of 90° between the peel tape and the adhesive material (Figure 1(a)).

When measuring the peel strength _P2 between adhesive material and wafer, the measurement can be performed using a sample for measuring peel strength _P2 without peel tape (Figure 1(b)).
A sample for measuring peel strength _P2 can be obtained, for example, by attaching the wafer-side adhesive layer of the adhesive material (23) to a polyimide-coated wafer (3) for measurement. In this case, treatment such as heating may be performed, simulating the actual wafer manufacturing process. The peel strength _P2 can be measured from the obtained sample for measuring peel strength _P2 by peeling off the adhesive material while maintaining an angle of 90° between the adhesive material and the wafer (Figure 1(b)).

The above peel strength ratio _P1 / _P2 is 6 or greater, preferably 6.5 or greater.
There is no particular upper limit to the above peel strength ratio _P1 / _P2 , but the above peel strength ratio _P1 / _P2 is preferably 30 or less, more preferably 25 or less, and particularly preferably 20 or less. From the viewpoint of appropriately peeling the adhesive from the laminate A consisting of the wafer and adhesive, it is desirable that the peel strength _P2 between the adhesive/wafer is not excessive, and from the viewpoint of preventing unintended peeling and adhesive residue between the peel tape and the adhesive, it is desirable that the peel strength _P1 between the peel tape and the adhesive is not insufficient. A peel strength ratio _P1 / _P2 of 6 or more can prevent unintended peeling and adhesive residue between the peel tape and the adhesive and adhesive residue on the wafer.

The peel strength _P1 is not particularly limited as long as it satisfies the above peel strength ratio _P1 / _P2 , but is preferably 3N/25mm or more. The peel strength _P1 is more preferably 5N/25mm or more, and particularly preferably 8N/25mm or more. Furthermore, the peel strength _P1 is not particularly limited as long as it satisfies the above peel strength ratio _P1 / _P2 , but is preferably 60N/25mm or less. The peel strength _P1 is more preferably 30N/25mm or less, and particularly preferably 20N/25mm or less.
By having a peel strength _P1 of 3N/25mm or more, when peeling the adhesive from a laminate A consisting of a wafer and adhesive, it is possible to prevent unintended peeling of the peel tape from the adhesive and adhesive residue from remaining on the wafer.

The peel strength _P2 is 0.5 N/25 mm or more. Preferably, the peel strength _P2 is 0.7 N/25 mm or more.
The upper limit of the peel strength _P2 is not particularly limited as long as the above peel strength ratio _P1 / _P2 is satisfied, but it is preferably 2.5 N/25 mm or less, and more preferably 2 N/25 mm or less.
A peel strength _P2 of 0.5 N/25 mm or higher prevents the wafer from separating from the support during processing such as thin grinding of the wafer. A peel strength _P2 of 2.5 N/25 mm or lower prevents unintended separation of the peel tape and temporary fixing material, as well as adhesive residue on the wafer, when peeling the adhesive material from the wafer.

There are no particular limitations on the means for adjusting the above-mentioned peel strength _P1 , peel strength _P2 , and peel strength ratio _P1 / _P2 , but they can be appropriately increased or decreased by means conventionally used in the art, for example. More specifically, they can be appropriately increased or decreased by the composition and manufacturing process of each layer, the manufacturing process of the laminate B consisting of a support/adhesive/wafer, etc., as described later. For example, the peel strength P1 and/or peel strength _P2 can be increased by using a highly polar polymer in the adhesive, adding tackifying resins such as polybutenes, rosin resins, terpene resins, petroleum resins, coumarone resins, or reducing the crosslinking component. On the other hand, the peel strength _P1 and/or peel strength _P2 can be decreased by adding a release agent to the adhesive, increasing the crosslinking component, or using a less polar polymer _, for example.

The adhesive used in the wafer manufacturing method of the present invention may have a single-layer structure or a laminated structure of multiple layers.

When the adhesive has a single-layer structure, the adhesive may have the same composition throughout; for example, it may be a single-layer tape containing an adhesive component. Alternatively, a semi-liquid or liquid curable adhesive may be used as a precursor to the adhesive. When using a semi-liquid or liquid curable adhesive, the semi-liquid or liquid adhesive can be applied to either the support or the wafer, or both, and then spin-coated. The support and wafer are then bonded together via the adhesive, and the adhesive component is cured to create a laminate B consisting of a support, adhesive, and wafer. After removing the support from the laminate B, the surface of the adhesive that was in contact with the support becomes surface A, which is in contact with the peel tape.

When the adhesive has a laminated structure of multiple layers, the layer having surface A in contact with the peel tape and the layer having surface B in contact with the wafer may have different compositions. In this case, the layer having surface A and the layer having surface B may have a layered structure in the general sense, where the composition changes discontinuously at their interface, or they may have a so-called gradient composition, where the composition changes continuously.

Furthermore, if the adhesive material has a laminated structure of multiple layers, it may be a so-called double-sided tape in which both the layer having surface A and the layer having surface B are adhesive layers. In this case, the layer having surface A can be configured to have a predetermined peel strength between the peel tape and the adhesive material, and the layer having surface B can be configured to have a predetermined peel strength between the adhesive material and the wafer.

The layer having surface A may be configured to consider the adhesive strength between the adhesive material and the support, as it comes into contact with the support in order to temporarily fix the wafer in the wafer support system. For example, when forming a laminate B consisting of a support/adhesive material/wafer by adhesively bonding the support and wafer using a semi-liquid or liquid adhesive and then curing the adhesive component, the layer having surface A of the adhesive material may contain a curable adhesive component.

Examples of adhesive components used in the adhesive layer of adhesive materials include those containing rubber-based, acrylic-based, epoxy-based, urethane-based, allyl-based, silicone-based, fluorine-based, and polyimide-based adhesive components. Acrylic or silicone-based adhesive components are preferred because they have heat resistance and allow for easy adjustment of adhesive strength. In particular, from the viewpoint of adjusting the adhesive strength with peel tape, if the layer having surface A of the adhesive material is the adhesive layer, it is preferable that the adhesive layer contains an acrylic-based adhesive component containing a silicone release agent.

The above adhesive component may be a curable adhesive component or a non-curable adhesive component. A curable adhesive component is preferred because curing it before heat treatment reduces the likelihood of voids forming during the heat treatment process, suppresses excessive adhesion due to high temperatures during heat treatment, and allows for easy peeling without leaving any adhesive residue.

Examples of the curing adhesive components mentioned above include photocuring adhesive components that crosslink and harden upon light irradiation, and thermosetting adhesive components that crosslink and harden upon heating.
Examples of the above-mentioned photocurable adhesive components and thermosetting adhesive components include those containing monomers, oligomers, or polymers such as acrylic, epoxy, urethane acrylate, epoxy acrylate, silicone acrylate, or polyester acrylate as curing components, and containing photopolymerization initiators or thermopolymerization initiators.

Among the above, the polymers of the acrylic adhesive components can be obtained, for example, by first synthesizing a (meth)acrylic polymer having a functional group in its molecule (hereinafter referred to as a functional group-containing (meth)acrylic polymer) and reacting it with a compound having a functional group that reacts with the above functional group and a radically polymerizable unsaturated bond in its molecule (hereinafter referred to as a functional group-containing unsaturated compound).

The above-mentioned functional group-containing (meth)acrylic polymer is obtained by copolymerizing, using conventional methods, an alkyl acrylate and/or alkyl methacrylate, which have an alkyl group with typically 2 to 18 carbon atoms, as the main monomer, along with a functional group-containing monomer and, if necessary, other modifier monomers that can copolymerize with these. The weight-average molecular weight of the above-mentioned functional group-containing (meth)acrylic polymer is typically around 200,000 to 2,000,000.

Examples of the above-mentioned functional group-containing monomers include carboxyl group-containing monomers such as acrylic acid and methacrylic acid, hydroxyl group-containing monomers such as hydroxyethyl acrylate and hydroxyethyl methacrylate, epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, isocyanate group-containing monomers such as isocyanate ethyl acrylate and isocyanate ethyl methacrylate, and amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate.

Other copolymerizable monomers for modification include, for example, various monomers commonly used in (meth)acrylic polymers such as vinyl acetate, acrylonitrile, and styrene.

As the functional group-containing unsaturated compound to be reacted with the above-mentioned functional group-containing (meth)acrylic polymer, the same as the functional group-containing monomers described above can be used depending on the functional group of the functional group-containing (meth)acrylic polymer. For example, if the functional group of the above-mentioned functional group-containing (meth)acrylic polymer is a carboxyl group, epoxy group-containing monomers or isocyanate group-containing monomers can be used. If the functional group is a hydroxyl group, isocyanate group-containing monomers can be used. If the functional group is an epoxy group, carboxyl group-containing monomers or amide group-containing monomers such as acrylamide can be used. If the functional group is an amino group, epoxy group-containing monomers can be used.

Examples of photopolymerization initiators include those activated by irradiation with light of a wavelength of 250 to 800 nm. Examples of such photopolymerization initiators include acetophenone derivative compounds such as methoxyacetophenone, benzoin ether compounds such as benzoin propyl ether and benzoin isobutyl ether, ketal derivative compounds such as benzyldimethyl ketal and acetophenone diethyl ketal, phosphine oxide derivative compounds, bis(η5-cyclopentadienyl) titanocene derivative compounds, benzophenone, Michler ketone, chlorothioxanthone, dodecylthioxanthone , dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexylphenyl ketone, and 2-hydroxymethylphenylpropane, which are photoradical polymerization initiators. These photopolymerization initiators may be used alone or in combination of two or more.

Examples of the above thermal polymerization initiators include those that decompose upon heat and generate active radicals that initiate polymerization curing. Specifically, examples include t-butylperoxy-2-ethyl hexanoate, bis(4-methylbenzoyl)peroxide, benzoyl peroxide, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(4,4-bis-(t-butylperoxy)cyclohexyl)propane, t-hexylperoxyisopropyl monocarboxylic acid, t-butylperoxyacetate, 2,2-bis- Examples include t-butylperoxy)butane, 4,4-bis-(t-butylperoxy)pentanoate n-butyl, bis-t-hexyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, bis(2-t-butylperoxyisopropyl)benzene, t-butylcumyl peroxide, di-t-butyl2,5-dimethyl-2,5-bis(t-butylperoxy)hexine peroxide, and diisopropylbenzene hydroperoxide.
While there are no particular limitations on commercially available thermal polymerization initiators, suitable examples include Perbutyl O, Niper BMT, Niper BW, Perhexa HC, Perhexa C, Pertetra A, Perhexyl I, Perbutyl A, Perhexa 22, Perhexa V, Perhexyl D, Permil D, Perhexa 25B, Perbutyl P, Perbutyl C, Perhexin 25B, Permil P (all manufactured by NOF Corporation), Percadox 12XL25 (manufactured by Kayaku Nourion Co., Ltd.), and others. These thermal polymerization initiators may be used individually or in combination of two or more.

The oligomer or monomer used as the curing component generally has a molecular weight of 10,000 or less and contains 1 to 40 radical polymerizable unsaturated bonds within the molecule. From the viewpoint of three-dimensional networking, two or more radical polymerizable unsaturated bonds are preferred.

Examples of the oligomers or monomers used as curing components include trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, or similar methacrylates. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylates, urethane acrylates, and similar methacrylates. These polyfunctional oligomers or monomers may be used individually or in combination of two or more.

The adhesive may optionally contain acrylic polymers without unsaturated double bonds, various thermal crosslinking agents such as isocyanate compounds, melamine compounds, and epoxy compounds, as well as known additives such as mold release agents, plasticizers, resins, surfactants, waxes, and fine particle fillers.

In adhesive materials, a release agent can preferably be used to adjust the peel strength between the peel tape and the adhesive material, and/or between the adhesive material and the wafer.

The aforementioned release agent is not particularly limited as long as it generally exhibits a release effect. Examples include hydrocarbon compounds, silicone compounds, fluorine compounds, and polyethylene waxes, carnauba waxes, montanic acid, and stearic acid, which are known as release agents for plastic materials.
Other release agents include plasticizers. Plasticizers are not particularly limited as long as they generally reduce the adhesive strength of the adhesive to the substrate. Examples of plasticizers include trimellitic acid esters, pyromellitic acid esters, phthalate esters, and adipic acid esters.

As the mold release agent, silicone-based and fluorine-based compounds are preferred, and silicone-based and fluorine-based compounds having functional groups that can be crosslinked with a curable adhesive are more preferred.
In particular, the silicone compound contained in the silicone release agent has excellent heat resistance, preventing scorching of the adhesive even after processing involving heating above 200°C, and facilitating peeling by bleeding out to the substrate interface. Because the silicone compound has functional groups that can crosslink with the curable adhesive, it chemically reacts with the curable adhesive upon light irradiation or heating and is incorporated into the curable adhesive, so the silicone compound does not adhere to the substrate and cause contamination. Furthermore, the inclusion of the silicone compound also has the effect of preventing adhesive residue on semiconductor chips.
In one embodiment of the present invention, the layer having surface A of the adhesive material may contain a silicone release agent.

The amount of release agent to be added is not particularly limited, but the amount should be appropriately determined to obtain a release effect. On the other hand, the amount should be controlled so as not to be excessive so as not to significantly impair the adhesive function of the adhesive material. For example, for 100 parts by mass of the total adhesive material, it is desirable to adjust the amount of release agent according to the release force, usually around 0.1 to 5 parts by mass, preferably 0.1 to 3 parts by mass, and more preferably 0.1 to 1 part by mass.

Furthermore, if a plasticizer is added, it is desirable to adjust the amount added according to the peeling force, typically using 5 to 50 parts by mass, preferably 10 to 50 parts by mass, and more preferably 20 to 40 parts by mass.
In this embodiment, these release agents can be used individually or in combination.

In one embodiment, the layer having surface A of the adhesive material may contain a silicone-based adhesive component or a silicone release agent. By containing a silicone-based adhesive component or a silicone release agent in the layer having surface A, the peel tape adheres to the edge of the adhesive material, making it easier to initiate the peeling of the adhesive material from the wafer. Therefore, the adhesive material can be more easily peeled from the laminate A consisting of the wafer and the adhesive material.

The thickness of the adhesive is not particularly limited, but a preferred lower limit is 5 μm and a preferred upper limit is 250 μm. A more preferred lower limit for the adhesive thickness is 10 μm and a more preferred upper limit is 200 μm. When the thickness of the adhesive is within this range, it can absorb the irregularities of the wafer, allowing for sufficient strength to be temporarily fixed to the support, and it is easier to adjust the peeling force to a suitable range when peeling off the adhesive.

In one embodiment, the adhesive used in the wafer manufacturing method of the present invention is preferably a so-called double-sided adhesive tape having a base film between a peel tape-side adhesive layer and a wafer-side adhesive layer. In this embodiment, the peel tape-side adhesive layer and the wafer-side adhesive layer can be designed from the viewpoint of optimizing the peel strength between the peel tape/adhesive and/or between the adhesive and wafer. The base film can be designed from the viewpoint of the adhesive itself, as well as the mechanical strength and handling properties of the laminate B consisting of the support/adhesive/wafer when the support and wafer are temporarily fixed, which is particularly advantageous from the viewpoint of optimizing the performance of the adhesive.
Figure 2 shows an example of a laminate consisting of peel tape/adhesive/wafer when using a double-sided tape having a base film between the wafer-side adhesive layer and the peel tape-side adhesive layer. In the figure, 11 is the base film of the peel tape, 12 is the adhesive layer of the peel tape, 22 is the peel tape-side adhesive layer of the adhesive, 21 is the base film of the adhesive, 23 is the wafer-side adhesive layer of the adhesive, and 3 is the wafer.

There are no particular limitations on the material of the base film for the adhesive, but it is preferable to use a plastic film. Examples include films, sheets, sheets with a mesh structure, and perforated sheets made of acrylic, olefin, polycarbonate, polyvinyl chloride, ABS, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), nylon, urethane, polyether ether ketone (PEEK), liquid crystal polymer (LCP), polyimide, polyester, and fluororesin. From the viewpoint of handling, PET, PEN, or polyimide films are preferred.

Peel tape is used to peel off the adhesive from a laminate A consisting of a wafer and the adhesive. The peel tape used in the wafer manufacturing method of the present invention has at least a base film and an adhesive layer, and the adhesive layer contains a silicone-based adhesive component.

Examples of silicone-based adhesive components include polyorganosiloxanes. Silicone-based adhesives include peroxide-curing adhesives obtained by adding silicone resin and organic peroxides to polyorganosiloxane, or addition-curing adhesives obtained by mixing polyorganosiloxane containing vinyl groups, silicone resin, and SiH-containing siloxane.

Because silicone-based adhesives have the property of wetting and spreading regardless of the adherend, when the peel tape is applied to the adhesive material of a laminate A consisting of a wafer and adhesive material, it is possible to adhere it sufficiently to the edges of the adhesive material. By adhering sufficiently to the edges of the adhesive material, it is possible to easily peel it off from the edges of the adhesive material. Compared to conventional technology, this makes it easier to initiate peeling and allows for stable peeling of the adhesive material from the laminate A consisting of a wafer and adhesive material.

Furthermore, in addition to the silicone-based adhesive component, various adhesive components and additives can also be used in the adhesive layer of the peel tape, from the viewpoint of adjusting the peel strength _P1 .

There are no particular limitations on the material used for the base film of the peel tape, but it is preferable to use a plastic film. Examples include films, sheets, sheets with a mesh structure, and perforated sheets made of acrylic, olefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), nylon, urethane, polyether ether ketone (PEEK), liquid crystal polymer (LCP), polyimide, polyester, and fluororesin. From the viewpoint of handling and adjusting the peel strength _P1 , the base film of the peel tape may preferably contain at least one of polyimide, polyester, or fluororesin.

In the wafer manufacturing method of the present invention, the adhesive can be peeled off from the laminate A, which consists of the adhesive and the wafer, by using the peel tape. There are no particular restrictions on the method of peeling off the adhesive, but for example, the peel tape can be uniformly attached to the surface A of the adhesive in the laminate A, which consists of the adhesive and the wafer, and one end of the peel tape can be peeled off in a direction of 10° to 180° relative to surface B. Since the peel tape can be sufficiently attached to the edge of the adhesive, it is possible to peel off the adhesive from the edge. Alternatively, the adhesive can be further peeled off by mechanical peeling or the like, using the edge of the adhesive peeled off from the wafer as a starting point.

In a wafer support system, the wafer is temporarily fixed to a support using an adhesive, and the wafer can be processed as a laminate B consisting of the support/adhesive/wafer, such as back grinding. After processing the wafer, the support is removed to obtain a laminate A consisting of the wafer and adhesive. In the wafer manufacturing method of the present invention, a step of peeling the adhesive from the laminate A consisting of the wafer and adhesive using a peel tape is included. There are no particular restrictions on the wafer, and any wafer generally used in semiconductor manufacturing processes can be manufactured. Among them, wafers that require careful handling during processing due to their thinness and fragility, and therefore require temporary fixing, are preferred. Here, the thinness and fragility of the wafer refer to cases where, for example, the thickness temporarily decreases during processing, causing difficulties in handling, and the adhesive is used to temporarily fix such wafers to the support. Cases where the wafer temporarily becomes thin include cases where a thin wafer is processed starting from the beginning, cases where a somewhat thick wafer is thinned during the process, and cases where a thinned wafer is further processed. The thickness of a temporarily thinned wafer is typically 1 to 200 μm.
For example, in a case where a semiconductor wafer with a completed functional layer is temporarily fixed to a support so that the functional layer faces the support, the opposite side (back side) of the functional layer is thinly ground, ion implantation, annealing, and electrode formation are performed on the back side, and then it is separated from the support, the semiconductor wafer in the process corresponds to the wafer.
As described above, wafers processed or manufactured by the manufacturing method of the present invention include those that undergo a change in state during the process.

As described above, there are no particular limitations on the wafers processed and manufactured using the wafer manufacturing method of the present invention. However, more specific examples include, for example, semiconductor wafers such as silicon wafers, SiC, AlSb, AlAs, AlN, AlP, BN, BP, BAs, GaSb, GaAs, GaN, GaP, InSb, InAs, InN, or InP compound semiconductor wafers, quartz wafers, sapphire, glass, molded wafers, etc.
Silicon wafers and compound semiconductor wafers may be doped.

An electrical/electronic functional layer may be formed on or within the wafer. Suitable examples of functional layers include electronic circuits, capacitors, transistors, resistors, electrodes, optical elements, MEMS, etc., but other microdevices may also be used.
The surfaces of these functional layers may have structures, typically electrodes, formed from one or more of the following materials: Materials for the functional layers include silicon, polysilicon, silicon dioxide, (oxy)silicon nitride, metals (e.g., copper, aluminum, gold, tungsten, tantalum), low-k dielectrics, polymer dielectrics, and various metal nitrides and metal silicides. The side of the wafer on which the functional layer is formed (the functional layer surface) may also have raised structures such as solder mounds, metal posts, and pillars.
Furthermore, the wafer surface may be covered with an oxide film or a nitride film for the formation or protection of a functional layer. Alternatively, the wafer surface may be covered with a passivation film for wafer protection.

A wafer manufactured by the wafer manufacturing method of the present invention can be subjected to further processes to manufacture a final product. If a functional layer is formed on the wafer, the final product can be manufactured by performing processes commonly used in the manufacture of electronic devices such as semiconductor devices, such as dicing, packaging, and encapsulation.

In measuring the peel strength _P2 of the present invention, a polyimide-coated wafer is used as the measurement wafer, as described above. The adhesive strength between the adhesive material and the wafer may change depending on the presence or absence of functional layers or films on the wafer surface. However, as long as the peel strength _P2 using a polyimide-coated wafer as the measurement wafer is within a predetermined range, it is possible to appropriately peel off the adhesive material without significantly affecting the peel strength ratio _P1 / _P2 , even with various wafers commonly used in wafer manufacturing processes.

Laminate A
According to the wafer manufacturing method of the present invention, a wafer can be obtained by peeling off the adhesive from a laminate A consisting of an adhesive and a wafer. The laminate A consisting of an adhesive and a wafer can be obtained, for example, by fixing a support to surface A of the adhesive and fixing a wafer to surface B to obtain a laminate B consisting of a support/adhesive/wafer, and then removing the support. The laminate B consisting of a support/adhesive/wafer has sufficient strength and rigidity, and the wafer can be used in various semiconductor manufacturing processes while preventing bending and breakage.

As a method for forming a laminate B consisting of a support, adhesive, and wafer, the support, adhesive, and wafer can be stacked in order. The stacking order is not particularly limited, and these layers may be stacked at once or sequentially.
When the adhesive is supplied as a liquid curable adhesive, the liquid curable adhesive can be applied to either a wafer or a support, or both, by spin coating, to form the adhesive or a precursor of the adhesive, and then a laminate can be created.
When an adhesive or adhesive precursor is supplied in the form of a solid film, the adhesive strength to the support is usually set lower than that to the wafer. Therefore, from the viewpoint of preventing peeling during handling, it is preferable to first attach the film to the wafer and then laminate the support.
Furthermore, when the film is attached at normal pressure and only the formation of the laminate is carried out under reduced pressure, it is preferable to first attach the film to the support and then attach it to the wafer, from the viewpoint of improving the absorption of wafer irregularities.

If the adhesive or precursor of the adhesive contains a curable adhesive component, the adhesive may be formed by irradiating or heating the curable adhesive component with light during the formation of the laminate to crosslink and cure the curable adhesive component.
The crosslinked and cured adhesive component, formed by light irradiation or heating, exhibits dramatically improved chemical resistance. This prevents the adhesive from dissolving into chemicals during wafer processing, such as when the back surface of the wafer is treated with a chemical solution. Furthermore, the increased elastic modulus of the crosslinked and cured adhesive component makes it less susceptible to increased adhesion even at high temperatures, resulting in relatively easy delamination.
Thus, in this embodiment, even though the wafer is subjected to heat treatment, machining, and/or wet treatment during the wafer processing steps, sufficient adhesive strength is maintained during wafer processing, and after the wafer processing steps are completed, the support is removed from the laminate B, and the wafer is peeled off from the laminate A without damaging the wafer or leaving any adhesive residue.

For example, when using a photocurable adhesive component that crosslinks and hardens upon light irradiation, and which contains a polymer having unsaturated double bonds such as vinyl groups in its side chains and a photopolymerization initiator activated at a wavelength of 250 to 800 nm, it is preferable to irradiate such a photocurable adhesive component with an illuminance of 5 mW or more, more preferably 10 mW or more, even more preferably 20 mW or more, and particularly preferable to irradiate with an illuminance of 50 mW or more. Furthermore, it is preferable to irradiate with an integrated illuminance of 300 mJ or more, more preferably 500 mJ or more and 10000 mJ or less, even more preferably 500 mJ or more and 7500 mJ or less, and particularly preferable to 1000 mJ or more and 5000 mJ or less.

Furthermore, for example, if a thermosetting adhesive component is used in which the adhesive or precursor of the adhesive crosslinks and hardens upon heating, and which contains a polymer having unsaturated double bonds such as vinyl groups in its side chains and a thermal polymerization initiator that is activated by heating at approximately 50 to 200°C, the thermosetting adhesive component can be crosslinked and hardened by heating at approximately 50 to 200°C for 10 to 60 minutes.

As described above, when forming an adhesive by curing a precursor of the adhesive, the adhesive may be laminated with a support or wafer after curing, cured after lamination, or laminated in a semi-cured state and then finally cured.

There are no particular limitations on the method for removing the support from the laminate B, which consists of a support, adhesive, and wafer. However, from the viewpoint of cost and convenience, it is preferable to remove it by mechanical peeling. There are no particular limitations on the method of mechanical peeling either, and peeling can be performed using commercially available equipment or the like as appropriate.

Support In the wafer manufacturing method of the present invention, before the step of peeling the adhesive from the laminate A consisting of the wafer and the adhesive, the wafer and the support can be temporarily fixed using the adhesive, and processing steps such as backside grinding of the wafer can be performed. The support is preferably one that has sufficient strength and rigidity and excellent heat resistance and chemical resistance. By using such a support, even when the wafer is thinly ground, it becomes possible to handle the wafer stably, and the wafer can be subjected to a large number and/or a wide range of processes without bending or other damage. For example, a wafer with an electronic circuit formed on it can be used in various processes necessary for manufacturing electronic devices having a structure in which semiconductor chips such as TSV connections are stacked.

Preferred materials for the support include silicon, sapphire, quartz, metals (e.g., aluminum, copper, steel), and various types of glass and ceramics. The support may be composed of a single material, multiple materials, or other materials deposited on the substrate. For example, it may have a vapor-deposited layer of silicon nitride or the like on a silicon wafer. It may also be surface-treated, such as by providing a silicone layer.

Depending on the process temperature in which the laminate is supplied, the support may be made of plastic. For example, sheets made of plastics such as polyimide, acrylic, polyolefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), nylon, and urethane can be preferably used as the support. Polyimide can be used because it has a certain degree of heat resistance.

To achieve uniformity in wafer thickness after grinding, it is desirable that the thickness of the support material be uniform. For example, to thin a silicon wafer to 50 μm or less and achieve a uniformity of ±10% or less, the variation in the thickness of the support material should be kept to ±2 μm or less.
There are no particular restrictions on the thickness of the support, but from the viewpoint of effectively preventing wafer bending, it is preferable to have a thickness of 300 μm or more, and particularly preferable to have a thickness of 500 μm or more. From the viewpoint of suppressing the total weight during handling or reducing the stress required for mechanical peeling, it is preferable to have a thickness of 1500 μm or less, and particularly preferable to have a thickness of 1000 μm or less.

Furthermore, the present invention is not limited to wafer manufacturing methods,
A method for peeling off an adhesive from a laminate A consisting of a wafer and an adhesive using a peel tape,
The method uses the peel tape containing a silicone-based adhesive component in the adhesive layer that contacts the adhesive material, and the adhesive material having _P1 and _P2 that satisfy the following conditions: the peel strength ratio _P1 / _P2 is 6 or more, and _P2 is 0.5 N/25 mm or more:
However, the adhesive material has a surface A that contacts the peel tape and a surface B that contacts the wafer, _P1 is the peel strength on surface A when the peel tape is held at 90° relative to the adhesive material and measured, and _P2 is the peel strength on surface B when the adhesive material is held at 90° relative to the polyimide coated wafer and measured.
It is also offered.

The peeling method of the present invention is not limited to the wafer manufacturing process, but can also be used to stably peel off the adhesive used for protection from a laminate A consisting of the wafer and the adhesive, for example, when a thinned wafer is protected with an adhesive during handling such as transportation. In this embodiment, the adhesive may be in the form of a protective tape having an adhesive layer.

The measurement conditions for the peel strength between the peel tape/adhesive and between the adhesive and wafer used in the peeling method of the present invention are as described above. From the viewpoint of contacting the adhesive with surface A, the peel tape contains a silicone-based adhesive component in the adhesive layer.

The adhesive used in the peeling method of the present invention is not particularly limited as long as it satisfies the above conditions, but preferably the layer having surface A of the adhesive contains a silicone adhesive component or a silicone release agent.
The silicone compound contained in the silicone release agent has excellent heat resistance, preventing scorching of the adhesive even after processing involving heating above 200°C, and facilitating peeling by bleeding out to the substrate interface. Furthermore, because the silicone compound has functional groups that can crosslink with curable adhesives that may be included as adhesive components, it chemically reacts with the curable adhesive upon light irradiation or heating and is incorporated into the curable adhesive, thus preventing the silicone compound from adhering to and contaminating the substrate. In addition, the inclusion of the silicone compound also has the effect of preventing adhesive residue on the wafer.
In particular, when the layer having surface A of the adhesive material is an adhesive layer, it is preferable that the adhesive layer contains a silicone release agent from the viewpoint of adjusting the adhesive strength with the peel tape. Particularly preferable is that the adhesive layer contains an acrylic adhesive component containing a silicone release agent. The silicone release agent allows for easy adjustment of the adhesive strength while maintaining heat resistance.

The adhesive material used in the peeling method of the present invention preferably comprises at least a wafer-side adhesive layer, a base film, and a peel tape-side adhesive layer. The adhesive components used in the wafer-side adhesive layer and the peel tape-side adhesive layer can be those described above. The base film can also be those described above.

According to the present invention, an adhesive material is provided for use in the aforementioned wafer manufacturing method or peeling method, wherein the peel strength _P2 is 0.5 N/25 mm or more. Hereinafter, the measurement conditions for the peel strength _P2 and the composition of the adhesive material are as described above.

The peel strength _P2 of the adhesive material of the present invention is 0.5 N/25 mm or more. Preferably, the peel strength _P2 is 0.7 N/25 mm or more.
The upper limit of the peel strength _P2 is not particularly limited as long as the above peel strength ratio _P1 / _P2 is satisfied, but it is preferably 2.5 N/25 mm or less, and more preferably 2 N/25 mm or less.
A peel strength _P2 of 0.5 N/25 mm or more prevents the wafer from separating from the support during processing such as wafer thinning. A peel strength _P2 of 2 N/25 mm or less prevents unintended separation of the peel tape from the adhesive and adhesive residue from remaining on the wafer when peeling the adhesive from the wafer.

From the viewpoint of adjusting the peel strength _P1 between the peel tape and the adhesive material of the present invention, the layer having surface A of the adhesive material that is in contact with the peel tape may contain a silicone adhesive component or a silicone release agent. By containing a silicone adhesive component or a silicone release agent in the layer having surface A, the peel tape adheres to the edge of the adhesive material, making it easier to initiate the peeling of the adhesive material from the wafer, and thus the adhesive material can be more easily peeled off the laminate A consisting of the wafer and the adhesive material. The silicone adhesive component and silicone release agent that can be used in the adhesive material of the present invention are as described above.

Furthermore, according to the present invention, a peel tape is provided for use in the aforementioned wafer manufacturing method or peeling method, wherein the peel tape comprises at least a base film and an adhesive layer, and the adhesive layer contains a silicone-based adhesive.

The adhesive layer of the peel tape of the present invention contains a silicone-based adhesive component.
Examples of the silicone-based adhesive component include polyorganosiloxane. The silicone-based adhesive includes peroxide-curing adhesives obtained by adding silicone resin and organic peroxide to polyorganosiloxane, or addition-curing adhesives obtained by mixing polyorganosiloxane containing vinyl groups, silicone resin, and SiH-containing siloxane. Because silicone-based adhesives have the property of wetting and spreading regardless of the adherend, the inclusion of a silicone-based adhesive component in the adhesive layer of the peel tape allows for sufficient adhesion to the edges of the adhesive material. Therefore, by ensuring sufficient adhesion to the edges of the adhesive material, it is possible to easily peel it off from the edges.

Furthermore, there are no particular limitations on the material used for the base film of the peel tape, and the aforementioned materials can be used. From the viewpoint of handling and adjusting the peel strength _P1 , the base film of the peel tape preferably contains at least one of polyimide, polyester, or fluororesin.

The present invention will be described in detail below. However, the present invention is not limited in any way by the following embodiments.

The physical properties and characteristics of the examples/comparative examples were evaluated by the following methods.

(1) Evaluation of the removeability of the adhesive from the wafer (1-1) Preparation of laminate A Laminate B was prepared by stacking a silicon wafer as the support and a polyimide coated wafer as the wafer in the order of support 7 / adhesive 23 (shown as a single layer structure for simplification) / wafer 3. Laminate B was heat-treated at 140°C for 30 minutes, then at 200°C for 30 minutes, and then fixed at room temperature with the polyimide coated wafer side down on a dicing tape 5 attached to a ring frame, and the dicing tape 5 was fixed by vacuum chuck (Figure 3(a)). With the intention of delaminating the interface between the silicon wafer (support 7) and the adhesive 23, the remover 8 was slid into the interface between the support 7 and the adhesive 23, and an upward force of typically up to about 120 N was applied to the edge of the silicon wafer (support 7) to form a delamination interface between the support 7 and the adhesive 23 that would initiate delamination (Figure 3(b)).
Next, pressure was applied to the formed delamination interface (Figure 3(c)) to expand the delamination interface, thereby delaminating the silicon wafer, which is the support, and creating a laminate A consisting of the wafer and adhesive material.

(1-2) Evaluation A laminate A consisting of 3 wafers/23 adhesive material (shown as a single-layer structure for simplification) fixed to 5 dicing tape attached to 6 ring frame was covered with a peel tape consisting of a base film of 11 peel tape and an adhesive layer of 12 peel tape. The 5 dicing tape was fixed with a vacuum chuck, and the peel tape consisting of 11 and 12 was lifted at a peeling angle of 90° and a peeling speed of 5 mm/s to peel off the 23 adhesive material. The peelability was evaluated according to the following criteria (Figure 4).
○: The adhesive was completely removed from the wafer, and no damage occurred to the wafer.
×: The adhesive could not be removed from the wafer.

(2) Measurement of peel strength _P1 (peel strength at surface A between peel tape and adhesive) (2-1) Preparation of sample for _P1 measurement Adhesive 1 or adhesive 2, described later, was cut to 3 cm x 5 cm and attached to a silicon wafer, which is the support, so that the adhesive layer on the peel tape side faced each other. A polyethylene terephthalate film (separator) treated with silicone release was attached to the adhesive layer on the wafer side (laminated body C). Laminate C was heated at 140°C for 30 minutes, and then heated at 200°C for 30 minutes, which is the same condition as the pretreatment in the formation process of laminate A. After that, the separator and silicon wafer were removed to obtain a sample for _P1 measurement.

(2-2) Measurement The wafer-side adhesive layer of the _P1 measurement sample prepared in (2-1) above was attached to an acrylic plate (not shown) via commercially available double-sided tape. The 12 adhesive layers of a 3 cm x 6 cm piece of peel tape were attached to the 22 adhesive layer on the peel tape side of the _P1 measurement sample, and the peel tape was trimmed to a width of 2.5 cm along with the _P1 measurement sample. Then, pressure was applied with a 2 kg roller for one back-and-forth motion. The peel strength P1 was measured at 22.5 ± 1 °C and 50 ± ₁₀ % relative humidity using VPA-S (manufactured by Kyowa Interface Science Co., Ltd.) at a tensile speed of 300 mm/min and a peeling angle of 90° (Figure 1(a)).

(3) Peel strength _P2 (Peel strength on surface B between adhesive material and wafer) measurement (3-1) Preparation of _P2 measurement sample Adhesive material 1 or adhesive material 2, described later, was cut to 3 cm x 5 cm and attached to a polyimide coated wafer so that the wafer-side adhesive layer faced each other, and then pressed with a 2 kg roller for one back-and-forth motion. A polyethylene terephthalate film (separator) treated with silicone release was attached to the peel tape side adhesive layer (laminated body D). Laminate D was heated at 140°C for 30 minutes, and then heated at 200°C for 30 minutes under conditions simulating the pretreatment in the formation process of laminate A. After that, the separator on the peel tape side adhesive layer was removed to obtain a sample for _P2 measurement.

(3-2) Measurement The _P2 measurement sample prepared in (3-1) above was cut to 2.5 cm x 5 cm, and the peel strength _P2 was measured at 22.5 ± 1 °C and 50 ± 10% relative humidity using VPA-S (manufactured by Kyowa Interface Science Co., Ltd.) at a tensile speed of 300 mm/min and a peeling angle of 90 degrees (Figure 1(b)).

Details of the materials used in the examples and comparative examples are as follows.
Support material and wafer
In verifying the removeability of the adhesive, silicon wafers and polyimide-coated wafers were used as the support and wafer, respectively.
A silicon mirror wafer with an outer diameter of 150 mm and a thickness of 625 μm was used.
- Polyimide coated wafer: A wafer was used in which a 5 μm polyimide film was applied to a Si mirror wafer with an outer diameter of 150 mm and a thickness of 625 μm.

Wafers used for measuring peel strength P2 _: The following wafers were used to measure the peel strength _P2 .
- Polyimide coated wafer: A wafer was used in which a 5 μm polyimide film was applied to a Si mirror wafer with an outer diameter of 150 mm and a thickness of 625 μm.

The following peel tapes were used in the peel tape examples and comparative examples.
• Peel Tape 1: No. 360UL (manufactured by Nitto Denko Corporation)
• Peel Tape 2: 5413 (manufactured by 3M Japan Limited)
• Peel Tape 3: 8992 (Manufactured by 3M Japan Limited)
- Peel tape 4: MHM-SI25 (manufactured by Nichiei Shinka Co., Ltd.) was backed with a 50 μm PET film.
• Peel Tape 5: ASF116T FR (manufactured by Chuko Chemical Industries Co., Ltd.)
• Peel Tape 6: No. 31B (manufactured by Nitto Denko Corporation)
- Peel tape 7: VHB BR-12 (manufactured by 3M Japan Ltd.) was backed with a 50 μm PET film.
• Peel Tape 8: Cellotape (registered trademark) (manufactured by Nichiban Co., Ltd.)

The resin used to form the adhesive layer of the adhesive material for forming the adhesive layer was prepared as follows.
(Meth)acrylic resin solution N
49 parts by mass of ethyl acrylate, 20 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of methyl acrylate, 10 parts by mass of glycidyl methacrylate, and 0.5 parts by mass of a benzoyl peroxide polymerization initiator were reacted at 80°C for 10 hours in a solvent consisting of 65 parts by mass of toluene and 50 parts by mass of ethyl acetate. After the reaction was complete, the resulting solution was cooled, and 25 parts by mass of xylene, 5 parts by mass of acrylic acid, and 0.5 parts by mass of tetradecyldimethylbenzylammonium chloride were added to the cooled solution and reacted at 85°C for 32 hours while blowing in air to obtain (meth)acrylic resin solution N.

The following films were used as the base film for the adhesive material.
- PEN film: Polyethylene naphthalate film (double-sided corona treated, thickness: 50 μm, manufactured by Toyobo Film Solutions Co., Ltd., Teonex Q83) was used.
- PET film: Biaxially oriented polyethylene terephthalate film (double-sided corona treated, 38 μm thick, manufactured by Toray Industries, Inc., Lumirror S10) was used.
- Polyimide film: A polyimide film (double-sided plasma treated, 38 μm thick, manufactured by Toray DuPont Ltd., product name: Kapton® 150EN-A) was used.

Adhesive material 1
To 270 parts by mass of a (meth)acrylic resin solution N, 2.84 parts by mass of HDI isocyanurate (manufactured by Tosoh Corporation, trade name: Coronate HX), 50 parts by mass of dipentaerythritol penta/hexaacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronics M-402), 2.0 parts by mass of silicone diacrylate (manufactured by Daicel Ornex Co., Ltd., trade name: Ebecryl 350), and 2 parts by mass of Percadox 12XL25 (manufactured by Kayaku Nurion Co., Ltd.) were added to obtain coating solution 1-1 for the adhesive layer on the support side (peel tape side). Coating solution 1-1 was applied to a base film (PEN film) and dried at 100°C for 10 minutes to form an adhesive layer 1-1 with a thickness of 25 μm as the adhesive layer on the support side (peel tape side). Next, a polyethylene terephthalate film (separator) treated with silicone release agent was laminated to obtain a laminate consisting of an adhesive layer 1-1 and a base film with a separator.
To 270 parts by mass of a (meth)acrylic resin solution N, 0.1 parts by mass of HDI isocyanurate (manufactured by Tosoh Corporation, trade name: Coronate HX), 30 parts by mass of dipentaerythritol penta/hexaacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronics M-402), 0.5 parts by mass of silicone diacrylate (manufactured by Daicel Ornex Co., Ltd., trade name: Ebecryl 350), and 2 parts by mass of Percadox 12XL25 (manufactured by Kayaku Nurion Co., Ltd.) were added to obtain coating solution 1-2 for the adhesive layer on the wafer side. Coating solution 1-2 was applied to a silicone-release-treated polyethylene terephthalate film (separator) and dried at 100°C for 10 minutes to form an adhesive layer 1-2 with a thickness of 40 μm as the adhesive layer on the wafer side. Next, the adhesive layer 1-2 was bonded to the substrate side of the laminate consisting of the adhesive layer 1-1 and the substrate film, thereby obtaining a laminate with a separator, consisting of three layers: adhesive layer 1-1, substrate film, and adhesive layer 1-2.
To 270 parts by mass of a (meth)acrylic resin solution N, 5.68 parts by mass of HDI isocyanurate (manufactured by Tosoh Corporation, trade name: Coronate HX), 30 parts by mass of dipentaerythritol penta/hexaacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronics M-402), 0.5 parts by mass of silicone diacrylate (manufactured by Daicel Ornex Co., Ltd., trade name: Ebecryl 350), and 2 parts by mass of Percadox 12XL25 (manufactured by Kayaku Nurion Co., Ltd.) were added to obtain coating solution 1-3 for the adhesive layer on the wafer side. Coating solution 1-3 was applied to a silicone-release-treated polyethylene terephthalate film (separator) and dried at 100°C for 10 minutes to form an adhesive layer 1-3 with a thickness of 10 μm on the wafer side. Next, the adhesive layer 1-3 was bonded to the adhesive layer 1-2 side of the laminate consisting of three layers: adhesive layer 1-1, base film, and adhesive layer 1-2, with the aforementioned separator, thereby producing a precursor of the adhesive material 1 before heat treatment, consisting of four layers: adhesive layer 1-1, base film, adhesive layer 1-2, and adhesive layer 1-3, with the separator.

Adhesive material 2
To 270 parts by mass of (meth)acrylic resin solution N, 2.84 parts by mass of HDI isocyanurate (manufactured by Tosoh Corporation, trade name: Coronate HX), 50 parts by mass of dipentaerythritol penta/hexaacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronics M-402), 2.0 parts by mass of acrylic group-containing polyether-modified polydimethylsiloxane (manufactured by BIC Chemie Japan Co., Ltd., trade name: BYK-UV3500), and 2 parts by mass of Percadox 12XL25 (manufactured by Kayaku Nurion Co., Ltd.) were added to obtain coating solution 2-1 for the adhesive layer on the support side (peel tape side). Coating solution 2-1 was applied to a base film (PEN film) and dried at 100°C for 10 minutes to form an adhesive layer 2-1 with a thickness of 25 μm as the adhesive layer on the support side (peel tape side). Next, a polyethylene terephthalate film (separator) treated with silicone release agent was laminated to obtain a laminate consisting of a separator-attached adhesive layer 2-1 and a base film.
To 270 parts by mass of (meth)acrylic resin solution N, 0.1 parts by mass of HDI isocyanurate (manufactured by Tosoh Corporation, trade name: Coronate HX), 30 parts by mass of dipentaerythritol penta/hexaacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronics M-402), and 2 parts by mass of Percadox 12XL25 (manufactured by Kayaku Nurion Co., Ltd.) were added to obtain coating solution 2-2 for the adhesive layer on the wafer side. The coating solution 2-2 was applied to a silicone-release-treated polyethylene terephthalate film (separator) and dried at 100°C for 10 minutes to form an adhesive layer 2-2 with a thickness of 40 μm as the adhesive layer on the wafer side. Next, the adhesive layer 2-2 was bonded to the substrate side of the laminate consisting of the adhesive layer 2-1/substrate film described above to obtain a laminate with a separator and a three-layer structure of adhesive layer 2-1/substrate film/adhesive layer 2-2.
To 270 parts by mass of a (meth)acrylic resin solution N, 5.68 parts by mass of HDI isocyanurate (manufactured by Tosoh Corporation, trade name: Coronate HX), 30 parts by mass of dipentaerythritol penta/hexaacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronics M-402), and 2 parts by mass of Percadox 12XL25 (manufactured by Kayaku Nurion Co., Ltd.) were added to obtain coating solution 2-3 for the adhesive layer on the wafer side. The coating solution 2-3 was applied to a silicone-release-treated polyethylene terephthalate film (separator) and dried at 100°C for 10 minutes to form an adhesive layer 2-3 with a thickness of 10 μm on the wafer side. Next, the adhesive layer 2-3 was bonded to the adhesive layer 2-2 side of the laminate, which has the above-mentioned separator-attached three-layer structure of adhesive layer 2-1/base film/adhesive layer 2-2, thereby producing a precursor of the adhesive material 2 before heat treatment, which has a four-layer structure of adhesive layer 2-1/base film/adhesive layer 2-2/adhesive layer 2-3 with a separator.

(Example 1)
Using adhesive material 1 and peel tape 1, the peel strengths _P1 and _P2 were measured according to the above-described peel strength measurement procedure, and _P1 / _P2 was calculated. As a result, _P1 / _P2 = 6.6.
Furthermore, following the confirmation of the removeability of the adhesive from the wafer described above, we investigated the removeability of the adhesive 1 from the wafer and found that the adhesive 1 could be completely peeled off the wafer without causing any damage to the wafer.

(Example 2)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 1, except that peel tape 2 was used. _P1 / _P2 = 6.8, indicating that the adhesive 1 could be completely peeled off the wafer without any damage to the wafer.

(Example 3)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 1, except that peel tape 3 was used. _P1 / _P2 = 7.8, indicating that the adhesive 1 could be completely peeled off the wafer without any damage to the wafer.

(Example 4)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 1, except that peel tape 4 was used. _P1 / _P2 = 11.9, indicating that the adhesive 1 could be completely peeled off the wafer without any damage to the wafer.

(Example 5)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 1, except that adhesive material 2 was used. _P1 / _P2 = 9.6, indicating that adhesive material 2 could be completely peeled off the wafer without any damage to the wafer.

(Example 6)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 2, except that adhesive material 2 was used. _P1 / _P2 = 9.3, indicating that adhesive material 2 could be completely peeled off the wafer without any damage to the wafer.

(Example 7)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 3, except that adhesive material 2 was used. _P1 / _P2 = 10.7, indicating that adhesive material 2 could be completely peeled off the wafer without any damage to the wafer.

(Example 8)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 4, except that adhesive material 2 was used. _P1 / _P2 = 16.2, indicating that adhesive material 2 could be completely peeled off the wafer without any damage to the wafer.

(Comparative Example 1)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 1, except that peel tape 5 was used. _P1 / _P2 = 4.2, indicating that the adhesive 1 could not be peeled from the wafer.

(Comparative Example 2)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 1, except that peel tape 6 was used. _P1 / _P2 = 5.0, indicating that the adhesive 1 could not be peeled from the wafer.

(Comparative Example 3)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 1, except that peel tape 7 was used. _P1 / _P2 = 10.0, indicating that the adhesive 1 could not be peeled from the wafer.

(Comparative Example 4)
The peel strengths _P1 and _P2 were measured in the same manner as in Example 1, except that peel tape 8 was used. _P1 / _P2 = 6.2, indicating that the adhesive 1 could not be peeled from the wafer.

(Comparative Example 5)
The peel strengths _P1 and _P2 were measured in the same manner as in Comparative Example 1, except that adhesive material 2 was used. _P1 / _P2 = 5.4, indicating that adhesive material 2 could not be peeled off the wafer.

(Comparative Example 6)
The peel strengths _P1 and _P2 were measured in the same manner as in Comparative Example 2, except that adhesive material 2 was used. _P1 / _P2 = 4.3, indicating that adhesive material 2 could not be peeled off the wafer.

(Comparative Example 7)
The peel strengths _P1 and _P2 were measured in the same manner as in Comparative Example 3, except that adhesive material 2 was used. _P1 / _P2 = 12.3, indicating that adhesive material 2 could not be peeled off the wafer.

(Comparative Example 8)
The peel strengths _P1 and _P2 were measured in the same manner as in Comparative Example 4, except that adhesive material 2 was used. _P1 / _P2 = 7.1, indicating that adhesive material 2 could not be peeled off the wafer.

Tables 1 and 2 show the combinations of peel tape and adhesive used in each example and comparative example, the results of the peel strength measurement, and the evaluation results of the removeability of the adhesive from the wafer.

The present invention provides a method for manufacturing wafers using the peel tape and adhesive, and the peel tape and adhesive used in this method allow for the execution of numerous and/or diverse processes on a wafer with high productivity and yield without damaging electronic components such as functional layers formed on the wafer. This significantly contributes to improving the productivity of electronic devices and has high applicability in various industrial fields, including the semiconductor process industry, the electronic components industry, the electrical and electronics industry using electronic components, the transportation machinery industry, the information and communication industry, and the precision equipment industry.

11: Base film of peel tape 12: Adhesive layer of peel tape 21: Base film of adhesive material 22: Adhesive layer on the peel tape side of the adhesive material 23: Adhesive layer on the wafer side of the adhesive material or single-layer adhesive material 3: Wafer 5: Dicing tape 6: Ring frame 7: Support 8: Remover

Claims (7)

A method for manufacturing wafers,
The process includes a step of peeling the adhesive from a laminate A consisting of a wafer and an adhesive using a peel tape, and in the step,
A method for manufacturing a wafer, using the peel tape containing a silicone-based adhesive component in the adhesive layer that contacts the adhesive material, and the adhesive material having _P1 and _P2 that satisfy the following conditions: the peel strength ratio _P1 / _P2 is 6 or more, and _P2 is 0.5 N/25 mm or more:
However, the adhesive material has a surface A that contacts the peel tape and a surface B that contacts the wafer, _P1 is the peel strength on surface A when the peel tape is kept at a 90° angle to the adhesive material and measured, and _P2 is the peel strength on surface B when the adhesive material is kept at a 90° angle to the polyimide coated wafer and measured .
The layer having surface A of the adhesive material contains a silicone-based adhesive component or a silicone release agent . The wafer manufacturing method according to claim 1, wherein the adhesive material comprises at least a wafer-side adhesive layer, a base film, and a peel-tape-side adhesive layer. A peeling method for removing an adhesive from a laminate A consisting of a wafer and an adhesive using a peel tape,
The peeling method uses the peel tape containing a silicone-based adhesive component in the adhesive layer that contacts the adhesive material, and the adhesive material having _P1 and _P2 that satisfy the following conditions: the peel strength ratio _P1 / _P2 is 6 or more, and _P2 is 0.5 N/25 mm or more:
However, the adhesive material has a surface A that contacts the peel tape and a surface B that contacts the wafer, _P1 is the peel strength on surface A when the peel tape is kept at a 90° angle to the adhesive material and measured, and _P2 is the peel strength on surface B when the adhesive material is kept at a 90° angle to the polyimide coated wafer and measured .
The layer having surface A of the adhesive material contains a silicone-based adhesive component or a silicone release agent . The peeling method according to claim 3 , wherein the adhesive material comprises at least a wafer-side adhesive layer, a base film, and a peel tape-side adhesive layer. A viscous adhesive used in the wafer manufacturing method described in claim 1 or the peeling method described in claim 3 , wherein _P2 is 0.5 N/25 mm or more. A peel tape used in the wafer manufacturing method described in claim 1 or the peeling method described in claim 3 , wherein the peel tape comprises at least a base film and an adhesive layer, and the adhesive layer contains a silicone-based adhesive. The peel tape according to claim 6 , wherein the base film of the peel tape comprises at least one of polyimide, polyester, or fluororesin.